In a large saucepan, melt margarine or butter over medium heat. Add onion and cook until golden, about 10 minutes, stirring occasionally. Whisk in flour and salt. Gradually stir in milk, chicken broth, and water.

Add cauliflower and heat to boiling over high heat. Reduce heat to low; cover and simmer until cauliflower is tender, about 15 minutes.In blender (with center part of blender cover removed to allow steam to escape), blend cauliflower mixture at low speed in small batches until very smooth. {Don't let this step deter you from making the soup! Blending it is really easy and so worth the extra 3 minutes. The most annoying part are the added dishes!}Return cauliflower mixture to saucepan; heat over medium heat until hot, stirring occasionally. Remove saucepan from heat; stir in mustard and 1 1/2 cups cheese until melted and smooth. Serve soup with remaining cheese as a garnish. (I added bacon on top as well. Everything is better with bacon).

Now for the bacon avocado grilled cheese sandwich...We just piled pepper jack cheese, cooked bacon, avocado, and tomatoes onto some bread and grilled it all together in a sandwich maker. Be sure to butter your bread before putting it on the grill. It's super easy and delicious. Soup and sandwiches are the perfect combo!